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Biomedical subjects

H Kindahl

Publications and source records attributed to H Kindahl.

At least 145 records · Page 8Linked to original sources
PubMed1989

Plasma concentrations of 15-keto-13,14-dihydro-PGF-2 alpha, oestrone sulphate, oestradiol-17 beta and progesterone in pregnant guinea-pigs treated with polychlorinated biphenyls.

Guinea-pigs treated by gavage with a total dose of 100 mg polychlorinated biphenyls (PCB: Clophen A50) during Days 17-61 of gestation had higher plasma concentrations of 15-keto-13,14-dihydroprostaglandin F-2 alpha, oestrone sulphate and oestradiol-17 beta during the later stages of gestation than did vehicle-treated guinea-pigs. No changes were observed in plasma progesterone concentrations. Our results provide no support for the hypothesis that an enzyme-induced decrease in progesterone concentrations is the main cause of the fetal death observed in PCB-treated guinea-pigs.

Animals↗
PubMed1989

The influence of flunixin on the response to Salmonella typhimurium endotoxin in calves.

The effects of intravenous injection of 0.5 microgram/kg body weight of Salmonella typhimurium endotoxin were studied in calves. The injection was followed by ruminal stasis and general dullness. The clinical signs disappeared within 24 hours. The injection was followed by a tremendous increase in the plasma level of 15-ketodihydro-PGF2 alpha, the main metabolite of PGF2 alpha. The injection was also associated with a profound leukopenia and significant decreases in the serum levels of iron, zinc and calcium. In order to study the role of prostaglandin (PG) for the development of endotoxin-induced changes a group of calves was pretreated with flunixin, a potent cyclo-oxygenase inhibitor, at a dose of 2.2 mg/kg body weight. Flunixin inhibited the PG release completely, but did not influence the other responses to endotoxin. The pyrogenic response to endotoxin was very moderate and it was suggested that fever is not the most suitable parameter for monitoring endotoxin effects in calves. The studied blood parameters (15-ketodihydro-PGF2 alpha, iron, zinc, calcium and the number of leukocytes) appeared to be much more sensitive.

Animals↗
PubMed1989

Endogenous prostaglandin F2 alpha release induced by physiologic saline solution infusion in utero in the mare: effect of temperature, osmolarity, and pH.

Thirty mares with normal estrous cycles were allotted equally to 5 groups and infused with 250 ml of saline (NaCl) solution in utero on the seventh day after ovulation to test the effects of temperature, osmolarity, or pH of the saline solution on prostaglandin F2 alpha (PGF2 alpha) release and luteolysis. Intrauterine infusion of phosphate-buffered saline solution failed to alter the duration of the luteal phase, compared with the control group. Similarly, increasing the temperature of phosphate-buffered saline solution to 42 C or increasing (600 mosm) or decreasing osmolarity (less than 10 mosm) did not change the duration of the luteal phase. Decreasing the pH of saline solution to 3 caused significant (P less than 0.0001) releases of PGF2 alpha from the uterus within the first hour after infusion, and the luteal phase was shortened to 8.8 +/- 1.0 days (mean +/- SEM; control, 15 +/- 1.2 days). The results of this study showed that pH is the main factor in eliciting PGF2 alpha release by intrauterine infusion of a saline solution, whereas increased temperature and osmolarity have no effect on the release of PGF2 alpha. The intrauterine infusion of sterile water or physiologic saline (NaCl) solution has been used to induce estrus in mares for the past 50 years. Many investigators have reported that intrauterine infusion of physiologic saline solution or water at body temperature (37 C) or warmer up to 45 C) causes most "anestrous" mares to return to estrus in 1 to 8 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Retained fetal membranes in cows: Manual removal versus nonremoval and its effect on reproductive performance.

Sixteen primiparous Holstein cows with retained fetal membranes (RFM) were studied for postpartum prostaglandin release, uterine infection and resumption of estrous cyclicity after manual removal of RFM (eight cows) versus leaving the RFM untreated (eight cows). The RFM were results of induced parturition on Day 274 of gestation. Seventeen non-RFM primiparous cows were controls. The 15-keto-13, 14-dihydro-metabolite of prostaglandin F(2alpha) (PGFM) was measured in daily blood samples. Aerobic and anaerobic bacteria were cultured from weekly uterine swabs from Week 3 until results were negative. Resumption of estrous cyclicity was determined by milk progesterone three times weekly. Manual removal caused an immediate and large but short-lived increase in PGFM, probably due to the physical damage of uterine tissue. No sustained difference in postpartum PGFM release between cows with RFM manually removed and cows with RFM left untreated was detected. Non-RFM controls had lowest PGFM concentrations. Uterine infections were more frequent and more severe after manual removal of RFM. Untreated RFM-cows and controls were similarly affected. Most infections involved Actinomyces (formerly Corynebacterium ) pyogenes and/or Fusobacterium necrophorum . Actinomyces pyogenes was isolated in the third week postpartum in 5 8 cows with RFM manually removed versus 2 8 cows with RFM left intact and in 2 17 controls. Manual removal prolonged the interval from calving to first functional corpus luteum by 20 d. This study, using RFM resulting from induced parturition, shows that manual removal of RFM can delay the postpartum return to normal reproductive status without altering PGFM profiles.

Journal Article↗
PubMed1988

Release of prostaglandin F-2 alpha and the timing of events associated with luteolysis in ewes with oestrous cycles of different lengths.

Ewes (N = 32) were bled every 2 h from 5 days before expected oestrus until the end of oestrus. Plasma concentrations were determined for progesterone to monitor luteal activity and for the prostaglandin F-2 alpha (PGF-2 alpha) metabolites, 15-keto-13,14-dihydro-PGF-2 alpha and 11-ketotetranor-PGF to determine uterine synthesis and release of PGF-2 alpha. Most of the variation in cycle length was associated with the time of onset of luteolysis, the timing of events after luteolysis being constant and not related to cycle length. The time of occurrence of the first PGF-2 alpha pulse and the interval between this pulse and the start of luteolysis were the two main determinants responsible for oestrous cycle length. Several PGF-2 alpha pulses with interpulse intervals of 15.9 h occurred before the onset of functional luteolysis compared with 7.7 h for pulses associated with luteolysis. The numbers of PGF-2 alpha pulses and interpulse intervals were similar for oestrous cycles of different lengths. While a gradual decline in progesterone concentrations was observed before functional luteolysis in the ewes with longer cycles, this did not appear to be an integral part of the stimulus which initiates the pulse frequency of PGF-2 alpha required for luteolysis. We therefore suggest that differences in oestrous cycle length in the ewe are determined by the time of the onset of PGF-2 alpha pulsatile release, and especially by the time of increased pulse frequency.

Animals↗
PubMed1988

Modification of prostaglandin F-2 alpha synthesis and release in the ewe during the initial establishment of pregnancy.

Pregnant (N = 10) and non-pregnant (N = 10) ewes were bled every 2 h from Days 12 to 17 after oestrus (oestrus = Day 0). Plasma concentrations of progesterone, 15-keto-13,14-dihydro-PGF-2 alpha and 11-ketotetranor-PGF metabolites were determined in all samples. The number of PGF-2 alpha pulses in non-pregnant ewes was 8.2 +/- 0.4 (mean +/- s.e.m.) with an interpulse interval of 10.7 +/- 0.7 h. Two or 3 pulses of low frequency (interpulse interval = 13.4 +/- 1.6 h) occurred in most non-pregnant ewes before the onset of luteolysis; the interpulse interval then decreased to 7.9 +/- 0.4 h for the 6.0 +/- 0.3 pulses temporally associated with luteolysis. In contrast, the number of PGF-2 alpha pulses in pregnant ewes was lower (2.5 +/- 0.7, 0-8) and the interpulse intervals longer (18.9 +/- 6.1 h). Most pulses occurred on Days 14 and 15 in the pregnant and non-pregnant ewes. The mean concentrations of both PGF-2 alpha metabolites in non-pregnant ewes were highest on Day 15 while basal levels of both metabolites remained constant at all times. In pregnant ewes, the mean concentrations of both metabolites were highest on Day 14; basal concentrations of both metabolites were also highest on Day 14. The mean concentrations of 15-keto-13,14-dihydro-PGF-2 alpha were higher in pregnant than in non-pregnant ewes on Days 13 and 14 (P less than 0.05) and higher in non-pregnant than pregnant ewes on Day 15 (P less than 0.05). The basal concentrations of the 15-keto metabolite were higher in pregnant than non-pregnant ewes at Days 13, 14, 15, 16 and 17 (P less than 0.05). Both the mean and the basal concentrations of 11-ketotetranor-PGF metabolites were higher in pregnant than in non-pregnant ewes on Day 14 (P less than 0.05). It is concluded that uterine production of PGF-2 alpha peaks at Days 14-15 after oestrus in pregnant and non-pregnant ewes. Patterns of release differ, however, in that non-pregnant ewes have a pulsatile PGF-2 alpha pattern superimposed on a constant baseline, while pregnant ewes have an increasing basal secretory pattern which is more nearly continuous, i.e. not pulsatile in form. Modification of pulsatile PGF-2 alpha synthesis and release is therefore a key aspect of prolongation of luteal function at the beginning of pregnancy in the ewe.

Animals↗
PubMed1987

Clinical and endocrine responses to embryonic and fetal death induced by manual rupture of the amniotic vesicle during early pregnancy in cows.

Pregnancy was terminated in 4 cows by manual rupture of the amniotic vesicle on day 41 (n = 1) and day 46 (n = 3) after insemination. Each cow was necropsied 36 days after vesicle rupture, by which time only one cow had come into estrus. Luteal activity, monitored daily by plasma progesterone assay, was still evident in 2 cows 35 days after fetal death; in the remaining 2 cows, regression of the corpus luteum (CL) was achieved at 28 and 32 days, respectively. Uterine release of prostaglandin F2 alpha (PGF2 alpha), measured as the 15-keto metabolite (PGFM) PGF2 alpha, was monitored by a plasma sampling schedule; specimens were obtained every 4 hours. There were no appreciable releases of PGF2 alpha associated with fetal death. The first appreciable PGF2 alpha release in episodic form was seen only in conjunction with CL regression. In all cows, a palpable membrane slip was evident for 18 days after rupture of the amniotic vesicle, although at that time, uterine resilience was diminished in the 2 cows in which the CL subsequently regressed. After 18 days, the uterus was noticeably edematous and fluid-filled in all cows; in 1 of the cows with a regressed CL, the uterus had returned to prepregnancy size and tone by day 33.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Prostaglandin biosynthesis and its regulation in the bovine endometrium: A comparison between nonpregnant and pregnant status.

Prostaglandin F(2alpha) (PGF(2alpha)), an arachidonic acid metabolism product of the prostaglandin synthetase pathway, is synthesized and released from the endometrium during luteolysis in nonpregnant animals. When proper conception occurs, the synthesis and release pattern is changed to maintain the corpus luteum (CL) function. The biosynthesis of prostaglandins in the bovine endometrium was highest in the microsomes but of low order. In nonpregnancy, the formation of prostaglandins from labelled precursor acid was higher than in pregnancy. Besides the prostaglandin synthetase, an inhibiting activity on the conversion of arachidonic acid to prostaglandins was found in both the nonpregnant and pregnant endometrium. During luteolysis (Day 17), a low inhibiting capacity was seen in comparison with other days of the estrous cycle (Days 1, 4 and 14). The inhibitory capacity was very high on Days 16 to 20, 25, and 31 of pregnancy. In the nonpregnant endometrium at Day 17, a very low inhibitor potency, calculated as IC(50) values, was found both in the cytoplasma and in the microsomes, whereas during early pregnancy (Days 17, 18, and 20) both cytoplasma and microsomes possessed very high inhibitor potency. This finding indicates that the bovine endometrium contains both prostaglandin synthetase and an unknown potent inhibitor of prostaglandin biosynthesis that regulates prostaglandin biosynthesis both during the estrous cycle and early pregnancy.

Journal Article↗
PubMed1987

Quality control of antibodies with special reference to prostaglandins.

Sources of error in the immunoassay of prostaglandins are reviewed. First, the specificity of the antibody, in terms of cross-reactions with structurally related substances, is often tested against irrelevant compounds, i.e. available compounds that do not occur in the biological material under study; major metabolises occurring in much larger amounts are overlooked. Hence, the reported high specificity of some antibodies may be apparent only. Second, many eicosanoids occur in two or more chemical forms in equilibrium in aqueous media. Antibodies may recognize one form preferentially; thus comparison of data from different laboratories is difficult. In addition numerous factors may interfere with the antigen-antibody binding in a non-immunological way. The most common effect is inhibition of antigen-antibody binding, but enhancement of binding sometimes occurs.

Journal Article↗
PubMed1987

Urinary levels of estrone sulfate and 11-ketotetranor prostaglandin F metabolite in pregnant guinea pigs given Clophen A50 (polychlorinated biphenyls).

The urinary levels of estrone sulfate and 11-ketotetranor prostaglandin F metabolite (11-ketotetranor PGF metabolite) during gestation in guinea pigs were measured by radioimmunoassays. Vehicle and Clophen A50 (polychlorinated biphenyls)-treated animals were compared. Gestation was arbitrarily divided into four periods, and the mean hormone levels during each period were compared between the two treatment groups. The Clophen A50 treatment (100 mg total, during Days 16-60), which causes fetal death, was correlated to significantly higher levels of estrone sulfate (p less than 0.05) and 11-ketotetranor PGF metabolite (p less than 0.01) during Days 47-60 (Period IV) of gestation.

Animals↗
PubMed1987

Effect of bovine virus diarrhoea virus on pregnancy in the ewe monitored by ultrasound scanning and levels of 15-keto-13,14-dihydro-PGF2 alpha and progesterone.

Fourteen unvaccinated and seronegative ewes were experimentally infected with bovine virus diarrhoea virus around day 60 of pregnancy. Two other groups of pregnant ewes served as control animals. The animals were followed with ultrasound scanning to study the status of the fetus and with frequent blood sampling for analysis of progesterone and 15-keto-13,14-dihydro-PGF2 alpha, two hormones that could reflect the propagation of the infection. The unvaccinated ewes responded to the infection with abortion, resorption of the fetus, mummification or no changes at all. The endocrinological changes reflected in a most adequate way the pathological changes in the uterus. Detailed endocrinological studies can contribute to the understanding of the pathogenesis of some infectious diseases that affect reproduction.

Abortion, Veterinary↗
PubMed1987

Endotoxin-induced prostaglandin (PGF2 alpha) biosynthesis, fever and miosis in dexamethasone-treated goats.

Prostaglandin-releasing, adrenocortical, febrile and miotic responses to endotoxin (ET) (E. coli lipopolysaccharide; 0.25 microgram kg-1) were studied in goats with and without prolonged dexamethasone influence. The i.v. injection of ET induced a three-fold peak elevation in plasma 15-ketodihydro-PGF2 alpha at 1.5 h post-injection, that is, between the first and second phase of the temperature elevation. During the latter phase, the plasma concentration of this primary PGF 2 alpha metabolite gradually returned to basal level, which implies that the second phase of ET fever is not PG dependent. The PG response exhibited a similar pattern, but was less pronounced in the dexamethasone-ET experiments, where the duration of maximum temperature elevation and of the miosis became shortened by about 20 min, and the typical biphasic pattern of ET fever was no longer seen. The ET-induced rise in plasma aldosterone concentration was completely blocked by dexamethasone. The corresponding rise in plasma cortisol concentration was prevented for 2 h, but was later only partially inhibited in spite of the repeated dexamethasone treatment.

Aldosterone↗